SIV infection of rhesus macaques is an excellent model for HIV infection of humans. Unfortunately, it has been difficult to identify macaques expressing particular MHC class I alleles. Here we describe the use of PCR-SSP for Mamu-A*01 typing of rhesus macaques. The Mamu-A*01 allele was amplified from genomic DNA using Mamu-A*01-specific primers and positive PCR products were directly sequenced. OBJECTIVE: To develop a robust technique for MHC typing of rhesus monkeys. RESULTS Our technique identified 15 Mamu-A*01-positive animals of 68 tested. We validated our molecular analysis by showing that lymphocytes from 8 Mamu-A*01-positive animals expressed Mamu-A*01 as determined by immunoprecipitation and 1-D IEF. FUTURE DIRECTIONS The technical simplicity and accuracy of this typing method should facilitate selection of Mamu-A*01-positive rhesus macaques for AIDS virus pathogenesis and vaccine studies. KEY WORDS MHC class I, DNA typing, PCR-SSP, direct sequencing, rhesus macaque, SIV, HIV